drm/i915: add needs_compact_pt flag

Add a new platform flag, needs_compact_pt, to mark the requirement of
compact pt layout support for the ppGTT when using 64K GTT pages.

With this flag has_64k_pages will only indicate requirement of 64K
GTT page sizes or larger for device local memory access.

v6:
	* minor doc formatting

Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220218184752.7524-6-ramalingam.c@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -1535,12 +1535,17 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 
 /*
  * Set this flag, when platform requires 64K GTT page sizes or larger for
- * device local memory access. Also this flag implies that we require or
- * at least support the compact PT layout for the ppGTT when using the 64K
- * GTT pages.
+ * device local memory access.
  */
 #define HAS_64K_PAGES(dev_priv) (INTEL_INFO(dev_priv)->has_64k_pages)
 
+/*
+ * Set this flag when platform doesn't allow both 64k pages and 4k pages in
+ * the same PT. this flag means we need to support compact PT layout for the
+ * ppGTT when using the 64K GTT pages.
+ */
+#define NEEDS_COMPACT_PT(dev_priv) (INTEL_INFO(dev_priv)->needs_compact_pt)
+
 #define HAS_IPC(dev_priv)		 (INTEL_INFO(dev_priv)->display.has_ipc)
 
 #define HAS_REGION(i915, i) (INTEL_INFO(i915)->memory_regions & (i))

drivers/gpu/drm/i915/i915_pci.c

@@ -1028,6 +1028,7 @@ static const struct intel_device_info xehpsdv_info = {
 	PLATFORM(INTEL_XEHPSDV),
 	.display = { },
 	.has_64k_pages = 1,
+	.needs_compact_pt = 1,
 	.platform_engine_mask =
 		BIT(RCS0) | BIT(BCS0) |
 		BIT(VECS0) | BIT(VECS1) | BIT(VECS2) | BIT(VECS3) |
@@ -1047,6 +1048,7 @@ static const struct intel_device_info dg2_info = {
 	PLATFORM(INTEL_DG2),
 	.has_guc_deprivilege = 1,
 	.has_64k_pages = 1,
+	.needs_compact_pt = 1,
 	.platform_engine_mask =
 		BIT(RCS0) | BIT(BCS0) |
 		BIT(VECS0) | BIT(VECS1) |

drivers/gpu/drm/i915/intel_device_info.h

@@ -128,6 +128,7 @@ enum intel_ppgtt_type {
 	/* Keep has_* in alphabetical order */ \
 	func(has_64bit_reloc); \
 	func(has_64k_pages); \
+	func(needs_compact_pt); \
 	func(gpu_reset_clobbers_display); \
 	func(has_reset_engine); \
 	func(has_global_mocs); \